Implantable devices for stimulating vagal nerves may be used to treat various medical conditions of a patient. Typically, an implantable device generates electrical pulses and delivers the electrical pulses to a vagal nerve of the patient to treat a particular medical condition. In many cases, this treatment can have the undesired effects of being uncomfortable to the patient, and causing a reduction in the patient's heart beat rate.
One approach to counter the slowing of the patient's heart beat rate is to stimulate the heart with pacing pulses. Thus, the vagal nerve is stimulated to treat the medical condition, and the heart is stimulated to maintain a normal heart beat rate during treatment. Stimulation of the heart during treatment, however, consumes power in the implantable device, which reduces the maximum possible duration for the treatment. Consequently, the medical condition may not be adequately treated with this approach.
In light of the above, there exists a need for stimulating a vagal nerve to treat a medical condition without pacing a patient's heart. There further exists a need for an implantable device that stimulates a vagal nerve for a prolonged period to treat a medical condition.